Performance Improvement of PEDOT:PSS/N-Si Heterojunction Solar Cells by Alkaline Etching

The design and fabrication of PEDOT:PSS/n-Si cell have been widely studied in recent years, yet few studies have looked into the effect of Si substrate properties on device’s performance. In this study, the thinning treatment of silicon substrates based on simple and low-cost alkaline etching has been systematically investigated. It is found that the KOH etching could effectively remove the surface damage layer. The series resistance (Rs) of device can be adjusted by silicon wafer thickness, under the optimized etching condition, the power conversion efficiency (PCE) of resulting 338 μm-thick PEDOT:PSS/n-Si could reach up to 5.17%, which is 1.7-times increase by comparing that of 500 μm-thick PEDOT:PSS/n-Si (PCE:2.97%).Furthermore, KOH-isopropanol texturing was incorporated into thinning silicon wafer, the smoothing pyramid structures can further reduce light reflectance and improve the junction contact quality between PEDOT:PSS film and n-Si substrates, and the PCE of 5.49% was finally achieved. This study shows guide value for understanding the influence of substrate thickness and texturing treatment on the performance of PEDOT:PSS/n-Si solar cell.